Ion Beam Induced Graphitization of Phenolformaldehyde

1993 ◽  
Vol 321 ◽  
Author(s):  
D. Ila ◽  
A. L. Evelyn ◽  
G. M. Jenkins

ABSTRACTWe have studied MeV ion beam induced phase transformation in phenolformaldehyde cured at 170°C by both Raman Microprobe spectroscopy and in situ resistance measurement of the irradiated area. Samples were irradiated using various doses of protons, alphas and nitrogen beams. Irradiated volumes in each sample were tested in situ for enhanced electrical conductivity and later on by Raman Microprobe spectroscopy. The results have shown changes in the resistance as much as seven orders of magnitude by alpha particles, six orders by nitrogen bombardment and three orders by hydrogen. Raman Microprobe spectroscopy of the darkened phase shows development of the D- and G-lines which are characteristic of the production of a carbonized resin. These spectra indicate that maximum carbonization was caused by the nitrogen beam.

1995 ◽  
Vol 396 ◽  
Author(s):  
A. L. Evelyn ◽  
D. Ila ◽  
J. Fisher ◽  
D. B. Poker

AbstractThe electronic and nuclear stopping effects produced by MeV ion bombardment in polyvinylidine chloride (PVDC) and polyethylene (PE) are separated by stacking thin films of the polymers. The resulting multi-layer laminates of each polymer were bombarded with 3.5 MeV alpha particles. The energy of the incident ions was selected, using TRIM, such that the first layers experienced most of the effects of the electronic energy deposited and the last layers received most of the effects of the nuclear stopping power. The changes in the conductance and the chemical structure of each layer were measured by direct resistivity measurements and Raman microprobe analysis.


1999 ◽  
Vol 569 ◽  
Author(s):  
C. Fery ◽  
W.E. Bailey ◽  
K. Yamada ◽  
S.X. Wang

ABSTRACTExposure to oxygen (1 Torr) at room temperature of thin Al films deposited by UHV ion beam sputtering has been studied using an in-situ resistance measurement set-up. Two lock-in amplifiers allow low noise data acquisition. By monitoring the conductance during deposition and oxidation we can deduce the consumed Al thickness as a function of exposure time (t). It is found that the Al/vacuum interface is diffuse for electron scattering. A two-stage mechanism for natural oxidation is revealed: fast growth (for t<10s) followed by a slow logarithmic growth. A simple model based on interface reactions and place exchange describes the experimental results. The conductance drop after 5 minutes of oxidation is found to decrease for initial Al thicknesses below 30A. This suggests the oxidation rates slow down for thin initial Al thicknesses.


Author(s):  
J. S. Maa ◽  
Thos. E. Hutchinson

The growth of Ag films deposited on various substrate materials such as MoS2, mica, graphite, and MgO has been investigated extensively using the in situ electron microscopy technique. The three stages of film growth, namely, the nucleation, growth of islands followed by liquid-like coalescence have been observed in both the vacuum vapor deposited and ion beam sputtered thin films. The mechanisms of nucleation and growth of silver films formed by ion beam sputtering on the (111) plane of silicon comprise the subject of this paper. A novel mode of epitaxial growth is observed to that seen previously.The experimental arrangement for the present study is the same as previous experiments, and the preparation procedure for obtaining thin silicon substrate is presented in a separate paper.


Author(s):  
Dudley M. Sherman ◽  
Thos. E. Hutchinson

The in situ electron microscope technique has been shown to be a powerful method for investigating the nucleation and growth of thin films formed by vacuum vapor deposition. The nucleation and early stages of growth of metal deposits formed by ion beam sputter-deposition are now being studied by the in situ technique.A duoplasmatron ion source and lens assembly has been attached to one side of the universal chamber of an RCA EMU-4 microscope and a sputtering target inserted into the chamber from the opposite side. The material to be deposited, in disc form, is bonded to the end of an electrically isolated copper rod that has provisions for target water cooling. The ion beam is normal to the microscope electron beam and the target is placed adjacent to the electron beam above the specimen hot stage, as shown in Figure 1.


Author(s):  
Charles W. Allen ◽  
Robert C. Birtcher

The uranium silicides, including U3Si, are under study as candidate low enrichment nuclear fuels. Ion beam simulations of the in-reactor behavior of such materials are performed because a similar damage structure can be produced in hours by energetic heavy ions which requires years in actual reactor tests. This contribution treats one aspect of the microstructural behavior of U3Si under high energy electron irradiation and low dose energetic heavy ion irradiation and is based on in situ experiments, performed at the HVEM-Tandem User Facility at Argonne National Laboratory. This Facility interfaces a 2 MV Tandem ion accelerator and a 0.6 MV ion implanter to a 1.2 MeV AEI high voltage electron microscope, which allows a wide variety of in situ ion beam experiments to be performed with simultaneous irradiation and electron microscopy or diffraction.At elevated temperatures, U3Si exhibits the ordered AuCu3 structure. On cooling below 1058 K, the intermetallic transforms, evidently martensitically, to a body-centered tetragonal structure (alternatively, the structure may be described as face-centered tetragonal, which would be fcc except for a 1 pet tetragonal distortion). Mechanical twinning accompanies the transformation; however, diferences between electron diffraction patterns from twinned and non-twinned martensite plates could not be distinguished.


Author(s):  
Jian-Shing Luo ◽  
Hsiu Ting Lee

Abstract Several methods are used to invert samples 180 deg in a dual beam focused ion beam (FIB) system for backside milling by a specific in-situ lift out system or stages. However, most of those methods occupied too much time on FIB systems or requires a specific in-situ lift out system. This paper provides a novel transmission electron microscopy (TEM) sample preparation method to eliminate the curtain effect completely by a combination of backside milling and sample dicing with low cost and less FIB time. The procedures of the TEM pre-thinned sample preparation method using a combination of sample dicing and backside milling are described step by step. From the analysis results, the method has applied successfully to eliminate the curtain effect of dual beam FIB TEM samples for both random and site specific addresses.


Author(s):  
H. Lorenz ◽  
C. Engel

Abstract Due to the continuously decreasing cell size of DRAMs and concomitantly diminishing thickness of some insulating layers new failure mechanisms appear which until now had no significance for the cell function. For example high resistance leakage paths between closely spaced conductors can lead to retention problems. These are hard to detect by electrical characterization in a memory tester because the involved currents are in the range of pA. To analyze these failures we exploit the very sensitive passive voltage contrast of the Focused Ion Beam Microscope (FIB). The voltage contrast can further be enhanced by in-situ FIB preparations to obtain detailed information about the failure mechanism. The first part of this paper describes a method to detect a leakage path between a borderless contact on n-diffusion and an adjacent floating gate by passive voltage contrast achieved after FIB circuit modification. In the second part we will demonstrate the localization of a DRAM trench dielectric breakdown. In this case the FIB passive voltage contrast technique is not limited to the localization of the failing trench. We can also obtain the depth of the leakage path by selective insitu etching with XeF2 stopped immediately after a voltage contrast change.


Author(s):  
Gunnar Zimmermann ◽  
Richard Chapman

Abstract Dual beam FIBSEM systems invite the use of innovative techniques to localize IC fails both electrically and physically. For electrical localization, we present a quick and reliable in-situ FIBSEM technique to deposit probe pads with very low parasitic leakage (Ipara &lt; 4E-11A at 3V). The probe pads were Pt, deposited with ion beam assistance, on top of highly insulating SiOx, deposited with electron beam assistance. The buried plate (n-Band), p-well, wordline and bitline of a failing and a good 0.2 μm technology DRAM single cell were contacted. Both cells shared the same wordline for direct comparison of cell characteristics. Through this technique we electrically isolated the fail to a single cell by detecting leakage between the polysilicon wordline gate and the cell diffusion. For physical localization, we present a completely in-situ FIBSEM technique that combines ion milling, XeF2 staining and SEM imaging. With this technique, the electrically isolated fail was found to be a hole in the gate oxide at the bad cell.


2016 ◽  
Vol 108 (21) ◽  
pp. 211902 ◽  
Author(s):  
Xian Chen ◽  
Nobumichi Tamura ◽  
Alastair MacDowell ◽  
Richard D. James

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